<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        a { display: block}
    </style>
</head>
<body>
    <a href="http://127.0.0.1:80/welcome.html">welcome 1</a>
    <a href="http://127.0.0.1/welcome.html">welcome 2</a>
    <a href="http://localhost:80/welcome.html">welcome 3</a>
    <a href="http://localhost/welcome.html">welcome 4</a>
    <a href="//127.0.0.1:80/welcome.html">welcome 5</a>
    <a href="welcome.html">welcome 6</a>

</body>
</html>